Flotation process.



BUDOLF GAHL, or mam;

ARIZONA, ASSIGNOR TO THE U-T AH COPPEB GOMPANY, A.

CORPORATION OF NEW JERSEY,

. FLOTATION. rnoonss.

1,290,166. t No Diawingl To all whom it may concern: Be it known that I,Rooonr GAHL, a

citizen of the United States, residing at Miami, in the county of Gilaand State of Arizona, have invented certain new and useful Improvementsin Flotation Processes, of

' which the following is a specification y This invention relates toso-called flotation processes for the concentration of ores,

and comprises a novel procedure by means of which the efiiciency ofthese flotation processes may-be very greatly improved, par

ticularly in their application to certain oreswhich are unsuited fortreatment by the ordinary methods. The invention will bedescribed-in'its application to the flotation of sulfid' or evencarbonate ores containing small percentages of copper, by means of air.bubbles used 1n conjunction .with suitable hydrocarbon substances, suchas coal-tar and It is believed, however, that allied products. thepresent improvement is'applicable to flotation processes in general, andthe invention is not therefore limited to the specific conditionsrecited by Way of example.

It. is a matter of common observation that vcertain ores or ore-batchesdo not respond well to the flotation treatment; and more or lessrefractory ores have been discovered wherever concentration by flotationhas been attempted. Even in ore bod1es consisting largely of goodflotation ores, portions are found which are less suited for thistreatment; and in ore mixtures which'res'pond well to flotation,portions can frequently be sorted out which do not" so respond whentreated by themselves; For this reason, the

mixing. of different ores has proven beneficial 1n a greatmany cases. Inmany cases, however, the ores necessary to constitute a properlyresponsive mixture are not available, and for such cases the processherein described Will prove particularly useful.

I have observed that ores which are refractory to the ordinary flotationtreatment can be handled without difiiculty, and with a reasonably highdegree of efficiency, provided there are added to the, ore, andthoroughly mixed therewith, certain solid sub stances which are notthemselves floated, and which do not apparently enter at all into theflotation reaction. Among such additions I Specification of LettersPatent.

Patented Jan. 2, 1919. p

ticularly effective when introduced in the form of filings or othersuitable state of fine subdivision. The iron may either be added inproper proportions to the feed entering the flotation machines, or itmay be introduoed at a; previous point in the treatment, for example inthe-grinding apparatus.

For example, if an .ore of the above-mentioned, imperfectly responsivetype containing a small percentage of copper in the form of sulfid, ismixed with one-half to two per cent, or evenless by weight of ironfilings, together with the usual proportion of oil or equivalentmaterial, and the Whole is subjected to flotation in water or the usualflotation media, under otherwise standard con ditions, air in the formof bubbles being injected or stirred into the mass, it will be foundthat the ore responds well to the treatment, and that excellentflotation eiiiciencies are obtained. The following tabular statement ofactual test runs upon a small scale 7 5 .Will serv to illustrate theresults which are obtalnable Per Grams Per Test Grams Grams GramsRecovcent. concencent.

copper. copper trate. copper. mpper' 86 F46 4s 25. 60 12. 29 81. 57 F47Y 27 s. so 2. as 15. 8%

F53 29 6. 16 p 1. 79 11.9% F54., 30 7.96 2.39 15.97 r55 59 21. 0s 12. 4482. 7 F56 56 25. 80 14. 45 95. 0%

L27 37 28. 42 10. 51 81. 7% L28 34 28. 96 9. 85 78. 3% L29 76 5. 66 4.30 '33. 4% L30 83 5. 06 4. 20 32. 9%

Referring to the above table,- tests marked F21, F22, F45, F46, F55,F56, were carried out with the addition to the 750 grams of ore of 10grams of iron filings. In tests F27 and F28, two grams of iron filingswere added. Tests F49 and F50 received ten grams of miscellaneous ironfilings from the machine shop, and tests F51 and F52 received the sameaddition, the latter tests being made however by a difierent observer.F48, F53, and F 54; were blanks, only the regular oils and flotationmedia were used, no iron being added.

Test F 64 was made ;with the samerefractory ore, but instead of grindingit in a mill filled with flint pebbles, it was ground in a mill filledwith steel balls, whereby particles.

of iron were introduced.

Tests L27 and L28 are blank tests on a good flotation ore, only theordinary flotation made under identical Tests L29 and L30 wereconditions, except 'for the addition of 10 grams Zinc filings.

It will be observed that with these particular ores, the eliiciency ofthe process was entirely dependent uponthe addition of iron.

The reasons underlying this observed effect are not as yet certainlyknown.

It is probable that the surface condition of oils being added.

. the iron exercises an important i fluence.

This is indicated by the fact which I have observed, that the additionof minute quantities of platinic chlorid to the solution materiallyincreases the quantity of foam formed when air'is blown through a porousdiaphragm into a suspension or solution of a frothing agent in water, towhich finely-difinely-divided iron vided iron has been added. In thiscase'it is assumed that a small percentage of the iron is-su'perficiallyreplaced by platinum.

Instead of mixing iro'n filings with the ore favorable results areobtained by introducing during the grinding or reduction process. Forexamplatest F64: in

the foregoing tabular statement illustrates. .theefiect of using steelmill instead 'ofthe flint pebbles usually employed for the finalreduction of the ore. In

balls in the grinding this case iron in minute subdivision .isthoroughly incorporated with the ore, owing to the abrasive e'fi'ectballs; and although goes oxidation during and after the grinding by theaction of the air and water, it is found that a certain portionof itpersists as metal, and tests have shown that the observed faof thelatter upon the vorable action upon the flotation is dueto this residualmetal and not to the iron oxid or hydroxid which accompanies it. WVhendesired, the proportion of iron thus introduced maybe increased by theuse of balls of softer iron or steel, by the addition to .the ore ofsome more highly abrasive material, bythe introduction of iron fromother sources, or by a combination of such methods.

.Not all forms of finely-divided iron are equally effective: forexample, when sponge iron was substituted for the iron filings, equallyfavorable results were not secured.

Furthermore, certain solid materials have been shown to exert adistinctly unfavorable effect upon theflotation process. For example,

Tests F47,

in whichthis iron largely underreferring to the foregoing tabular-1,2e0,1ce I statement (tests L27 to L30, inclusive), it will be notedthat the addition of a small proportion of zinc filings very markedlydecreased the flotation efiiciency in the case of a normally goodflotation ore.

It is obviously impossible to name all of the substanceswvhich mayultimately prove available for increasin the flotation efliciency,although the avai ability ofa'ny given substance is readily determinedby simple ex periment in. the light of the information herein lven. heris it possible at the presout time to define such available substancesby a classification based upon other chemical or physical propertiesWhichthey may pcstageously used for accomplishing a separation of'thekind described. Combinations of machines of various typesmay.be.employed. For instance, wherefconcentrating tables-are used forre-treating flotation tailings, metallic iron will largely go into thetable concentrates, and may by means of magnets and conveyer belts, betransferred again to the flotation machine. 4 i

Although so far as is now known, the substances to be used as additionsto theore in accordance with this invention are active only in solidform, it is to'be understood that they may be introduced in solution,chemical reactions 'bein'g' relied upon to precipitate them in theactive solid form, as in the example of platinic chlorid above referredto. The present process is quite independentof special apparatus, andmay be carried.

out in any of the standard forms of flotation machines now on themarket. The ore'is either ground with the flotation agent, or issubsequently agitated therewitl The air bubbles may be introduced'asdesired by any of the known methods, such as application of. a vacuum,injection through a porous bottom, or by drawing or blowing air into thepulp and distributing it therethrough in the form of small bubbles byviolent'agita-,

tion.

1. A process of concentrating ores by bubble-flotation, which consistsin mixing the ore with an extraneous solid capable of increasing theefliciency oi the flotation, concentrating the mixture by flotation,recovering the said extraneous solid from the floore, concentrating themixture by flotation, tation tailings, and applying the recoveredrecovering the metallic iron from the flotasolid in the flotation ofother bodies of ore. tion tailings, and applying the recovered 2. Aprocess of concentrating ores by iron in the flotation of further bodiesof ore. 1O 5 bubble-flotation which consists in mixing In testimonywhereof I affix my signature. iron in suitably subdivided form with theRUDOLF GAHL.

